Signaling Pathways, Chemical and Biological Modulators of Nucleotide Excision Repair: The Faithful Shield against UV Genotoxicity

Figure 1

DNA lesions induced by damaging agents. Several DNA lesions are formed upon the exposure of the DNA to harmful insults. Replication errors can give rise to insertion, deletion, or base mismatch mutations. Alkylating agents and reactive oxygen species (ROS) can lead to the formation of abasic sites, single-strand breaks (SSB), and 8-oxoguanines. On the other hand, UV radiation and chemical agents mediate the formation of pyrimidine dimers and the addition of bulky adducts. Finally, ionizing radiation including X-rays and antitumor drugs can lead to single-strand breaks and double-strand breaks, together with inter- and intrastrand cross-links. ROS: reactive oxygen species; SSB: single-strand breaks; DSB: double-strand breaks; IR: ionizing radiation.